| Acknowledgement | 第1-6页 |
| 摘要 | 第6-7页 |
| Abstract | 第7-8页 |
| List of Table | 第8-11页 |
| Chapter One Introduction | 第11-13页 |
| ·Origin of the study | 第11-12页 |
| ·Objective of the study | 第12页 |
| ·Layout of the paper | 第12-13页 |
| Chapter Two Literature Review | 第13-26页 |
| ·Study on DMs abroad | 第13-23页 |
| ·Definitions of DMs | 第13-15页 |
| ·Properties of DMs | 第15-17页 |
| ·Optionality | 第15页 |
| ·Connectivity | 第15-16页 |
| ·Pragmatic motivation | 第16-17页 |
| ·Approaches to the study of DMs | 第17-23页 |
| ·Grammatical-pragmatic approach | 第17-18页 |
| ·Coherence-based approach | 第18-22页 |
| ·Relevance-theoretical approach | 第22-23页 |
| ·Study on DMs at home | 第23-24页 |
| ·A brief description of I think as a DM | 第24-26页 |
| Chapter Three Research Methodology | 第26-30页 |
| ·Corpus and corpus-based approach | 第26-27页 |
| ·Corpora in use | 第27-28页 |
| ·Analytical tool | 第28-29页 |
| ·Research questions | 第29-30页 |
| Chapter Four Findings and Discussions | 第30-60页 |
| ·Results and data analysis | 第30-37页 |
| ·The overall frequencies of DM I think in SECCL and CF | 第30-31页 |
| ·Collocation of DM I think in SECCL and CF | 第31-37页 |
| ·Pragmatic functions of DM I think | 第37-50页 |
| ·Pragmatic functions of DM I think in CF | 第38-43页 |
| ·To take the turn | 第38-39页 |
| ·To hold the turn | 第39-41页 |
| ·To show politeness | 第41-43页 |
| ·Pragmatic functions of DM I think in SECCL | 第43-48页 |
| ·Turn taking | 第44-45页 |
| ·Turn holding | 第45-46页 |
| ·Downgrader | 第46-48页 |
| ·Inappropriate uses of DM I think by Chinese EFL learners | 第48-50页 |
| ·To emphasize ‘I am expressing my opinion’ | 第48-49页 |
| ·To signal self-repair and reformulation | 第49-50页 |
| ·Possible reasons for the inappropriate uses of DM I think by Chinese EFL learners | 第50-60页 |
| ·Pragmatic transfer | 第51-54页 |
| ·Pragmatic fossilization | 第54-57页 |
| ·Situational anxiety | 第57-58页 |
| ·Little instruction in DMs | 第58-60页 |
| Chapter Five Conclusion | 第60-64页 |
| ·Summary of the present study | 第60-61页 |
| ·Pedagogical significance | 第61-62页 |
| ·Limitations and suggestions for further study | 第62-64页 |
| Bibliography | 第64-68页 |
| Appendix | 第68-77页 |
